Scandium has apparently never been recovered from titanium ore. While there are scandium ores, such ores are rare (as noted in U.S. Pat. No. 2,874,039, to Pruvot et al., which discloses a process for extraction of scandium from thorveitite ore).
The separation of rare earths from ores by leaching (including with hydrochloric acid in one instance) is discussed in U.S. Pat. Nos. 2,722,471 (to Hirsch et al), 3,812,233 (to Duncan), and 2,735,747 (to Kasey). The separation of rare earths from thorium (including in acid leach liquors in one instance) is discussed in U.S. Pat. Nos. 2,990,244 (to Brown et al), 3,159,452, (to Lerner), and 3,087,948 (to Carter et al). The reduction of scandium chloride to metal is discussed in U.S. Pat. No. 2,941,867 (to Maurer).
Titanium ore is used for the production of titanium metal and titanium oxide. The converting titanium ore (titanium ore) to titanium metal generally utilizes the following operations: chlorination, reduction, distillation (magnesium chloride and Mg vaporization for their removal from the titanium), and double (or triple) arc melting to produce an ingot. The titanium ingot can be then fabricated into various shapes.
With regard to chlorination, U.S. Pat. No. 4,244,935, issued to Dell on Jan. 13, 1981, relates a method of forming the chloride of a metal-oxygen containing substance based on a fluid coking technique. It should be noted that the commercial process for making titanium metal utilizes a fluidized bed carbochlorination process (e.g. of rutile, generally titanium oxide, or ilmenite, generally titanium and iron oxides, ores) at about 1000.degree. C. (temperature across the bed apparently varies up to 200.degree. C. or so), which produces titanium tetrachloride. U.S. Pat. No. 3,895,097, issued to Langenhoff et al. on July 15, 1975, also relates to a process for reacting metal oxides with chlorine.
Commercially, reduction is by reacting gaseous titanium tetrachloride with molten magnesium to produce titanium metal (in relatively porous, so-called "sponge", form). Modifications to the reduction process have been suggested in many U.S. Pat. Nos., including 4,440,384; 4,511,399; 4,556,420; 4,613,366; 4,637,831 and 4,668,287, assigned to the same assignee.
With regard to "distillation" to remove magnesium chloride and Mg (by their vaporization) from the titanium sponge, such distillation is usually performed at about 1050.degree.-1100.degree. C. (note, however that Kwon et al. in U.S. Pat. No. 4,711,664 teach that iron content can be lowered by distilling at about 934.degree. C.).
Consumable electrode vacuum arc melting is generally used to produce a consolidated ingot from the porous distilled sponge (generally the distilled sponge is broken up and then pressed into disks, for example, which disks are then welded together to form the consumable electrode. An improved consumable electrode is described in Weber's U.S. Pat. No. 4,539,688.
Recovery of materials from waste streams, is, of course, desirable. For example, Naitou et al. in U.S. Pat. No. 4,650,652, issued Mar. 7, 1987, describe a process for recovering high purity rare earth oxides from a waste rare earth phosphor (the process utilizes dissolving waste rare earth phosphor in an excess amount of acid, adding oxalic acid to obtain precipitates of rare earth oxalates, washing precipitates and baking precipitates).